United States Court of Appeals for the District of Columbia Circuit
United States Court of Appeals for the Federal Circuit

United States Circuit Court of the District of Columbia was created in 1801.

United States Circuit Court of the District of Columbia ended in 1863.

There is no Court of Appeals named as the Twelfth Circuit; it is called the US Court of Appeals for the District of Columbia. As the name implies, the Circuit only covers appellate cases for the District of Columbia.

The United States District Court for the District of Massachusetts is the lower court under the United States Court of Appeals for the First Circuit.